Filling the pool

How many liters of water must be poured into a pool 25 m long, 800 cm wide, and 20 m deep? The pool should be filled to 3/4 of its depth. How many euros will you pay for pool tiling, and a square meter of tiling costs 20 euros?

Final Answer:

V =  300000 l
x =  6640 Eur

Step-by-step explanation:

$$\begin{gathered} a=25\text{m} \\ b=800\text{cm}\to \text{m}=800:100\text{m}=8\text{m} \\ c=20\text{dm}\to \text{m}=20:10\text{m}=2\text{m} \\ {V}_1=a\cdot b\cdot c=25\cdot 8\cdot 2=400{\text{m}}^3 \\ {V}_2=\frac{3}{4}\cdot V_1=\frac{3}{4}\cdot 400=\frac{3\cdot 400}{4}=\frac{1200}{4}=300{\text{m}}^3 \\ V=V_2\to \text{l}=V_2\cdot 1000\text{l}=300\cdot 1000\text{l}=300000\text{l}=300000\text{l} \end{gathered}$$

$$\begin{gathered} p=20{\text{Eur/m}}^2 \\ S=a\cdot b+2\cdot (a+b)\cdot c=25\cdot 8+2\cdot (25+8)\cdot 2=332{\text{m}}^2 \\ x=p\cdot S=20\cdot 332=6640\text{Eur} \end{gathered}$$

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